AppMon is an automated framework for monitoring and tampering system API calls of native apps on iOS, Mac OS X and Android apps (upcoming). You may call it the GreaseMonkey for native mobile apps. 😉
AppMon is my vision is to make become the Mac OS X/iOS/Android equivalent of the this project apimonitor and GreaseMonkey. This should become a useful tool for the mobile penetration testers to validate the security issues report by a source code scanner and by inspecting the APIs in runtime and monitoring the app’s overall activity and focus on things that seem suspicious. You can also use pre-defined user-scripts to modify the app’s functionality/logic in the runtime e.g. spoofing the DeviceID, spoofing the GPS co-ordinates, faking In-App purchases, bypassing TouchID etc.